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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2021, Red Hat, Inc.
*
* Tests for Hyper-V clocksources
*/
#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
#include "hyperv.h"
struct ms_hyperv_tsc_page {
volatile u32 tsc_sequence;
u32 reserved1;
volatile u64 tsc_scale;
volatile s64 tsc_offset;
} __packed;
/* Simplified mul_u64_u64_shr() */
static inline u64 mul_u64_u64_shr64(u64 a, u64 b)
{
union {
u64 ll;
struct {
u32 low, high;
} l;
} rm, rn, rh, a0, b0;
u64 c;
a0.ll = a;
b0.ll = b;
rm.ll = (u64)a0.l.low * b0.l.high;
rn.ll = (u64)a0.l.high * b0.l.low;
rh.ll = (u64)a0.l.high * b0.l.high;
rh.l.low = c = rm.l.high + rn.l.high + rh.l.low;
rh.l.high = (c >> 32) + rh.l.high;
return rh.ll;
}
static inline void nop_loop(void)
{
int i;
for (i = 0; i < 100000000; i++)
asm volatile("nop");
}
static inline void check_tsc_msr_rdtsc(void)
{
u64 tsc_freq, r1, r2, t1, t2;
s64 delta_ns;
tsc_freq = rdmsr(HV_X64_MSR_TSC_FREQUENCY);
GUEST_ASSERT(tsc_freq > 0);
/* For increased accuracy, take mean rdtsc() before and afrer rdmsr() */
r1 = rdtsc();
t1 = rdmsr(HV_X64_MSR_TIME_REF_COUNT);
r1 = (r1 + rdtsc()) / 2;
nop_loop();
r2 = rdtsc();
t2 = rdmsr(HV_X64_MSR_TIME_REF_COUNT);
r2 = (r2 + rdtsc()) / 2;
GUEST_ASSERT(r2 > r1 && t2 > t1);
/* HV_X64_MSR_TIME_REF_COUNT is in 100ns */
delta_ns = ((t2 - t1) * 100) - ((r2 - r1) * 1000000000 / tsc_freq);
if (delta_ns < 0)
delta_ns = -delta_ns;
/* 1% tolerance */
GUEST_ASSERT(delta_ns * 100 < (t2 - t1) * 100);
}
static inline u64 get_tscpage_ts(struct ms_hyperv_tsc_page *tsc_page)
{
return mul_u64_u64_shr64(rdtsc(), tsc_page->tsc_scale) + tsc_page->tsc_offset;
}
static inline void check_tsc_msr_tsc_page(struct ms_hyperv_tsc_page *tsc_page)
{
u64 r1, r2, t1, t2;
/* Compare TSC page clocksource with HV_X64_MSR_TIME_REF_COUNT */
t1 = get_tscpage_ts(tsc_page);
r1 = rdmsr(HV_X64_MSR_TIME_REF_COUNT);
/* 10 ms tolerance */
GUEST_ASSERT(r1 >= t1 && r1 - t1 < 100000);
nop_loop();
t2 = get_tscpage_ts(tsc_page);
r2 = rdmsr(HV_X64_MSR_TIME_REF_COUNT);
GUEST_ASSERT(r2 >= t1 && r2 - t2 < 100000);
}
static void guest_main(struct ms_hyperv_tsc_page *tsc_page, vm_paddr_t tsc_page_gpa)
{
u64 tsc_scale, tsc_offset;
/* Set Guest OS id to enable Hyper-V emulation */
GUEST_SYNC(1);
wrmsr(HV_X64_MSR_GUEST_OS_ID, HYPERV_LINUX_OS_ID);
GUEST_SYNC(2);
check_tsc_msr_rdtsc();
GUEST_SYNC(3);
/* Set up TSC page is disabled state, check that it's clean */
wrmsr(HV_X64_MSR_REFERENCE_TSC, tsc_page_gpa);
GUEST_ASSERT(tsc_page->tsc_sequence == 0);
GUEST_ASSERT(tsc_page->tsc_scale == 0);
GUEST_ASSERT(tsc_page->tsc_offset == 0);
GUEST_SYNC(4);
/* Set up TSC page is enabled state */
wrmsr(HV_X64_MSR_REFERENCE_TSC, tsc_page_gpa | 0x1);
GUEST_ASSERT(tsc_page->tsc_sequence != 0);
GUEST_SYNC(5);
check_tsc_msr_tsc_page(tsc_page);
GUEST_SYNC(6);
tsc_offset = tsc_page->tsc_offset;
/* Call KVM_SET_CLOCK from userspace, check that TSC page was updated */
GUEST_SYNC(7);
/* Sanity check TSC page timestamp, it should be close to 0 */
GUEST_ASSERT(get_tscpage_ts(tsc_page) < 100000);
GUEST_ASSERT(tsc_page->tsc_offset != tsc_offset);
nop_loop();
/*
* Enable Re-enlightenment and check that TSC page stays constant across
* KVM_SET_CLOCK.
*/
wrmsr(HV_X64_MSR_REENLIGHTENMENT_CONTROL, 0x1 << 16 | 0xff);
wrmsr(HV_X64_MSR_TSC_EMULATION_CONTROL, 0x1);
tsc_offset = tsc_page->tsc_offset;
tsc_scale = tsc_page->tsc_scale;
GUEST_SYNC(8);
GUEST_ASSERT(tsc_page->tsc_offset == tsc_offset);
GUEST_ASSERT(tsc_page->tsc_scale == tsc_scale);
GUEST_SYNC(9);
check_tsc_msr_tsc_page(tsc_page);
/*
* Disable re-enlightenment and TSC page, check that KVM doesn't update
* it anymore.
*/
wrmsr(HV_X64_MSR_REENLIGHTENMENT_CONTROL, 0);
wrmsr(HV_X64_MSR_TSC_EMULATION_CONTROL, 0);
wrmsr(HV_X64_MSR_REFERENCE_TSC, 0);
memset(tsc_page, 0, sizeof(*tsc_page));
GUEST_SYNC(10);
GUEST_ASSERT(tsc_page->tsc_sequence == 0);
GUEST_ASSERT(tsc_page->tsc_offset == 0);
GUEST_ASSERT(tsc_page->tsc_scale == 0);
GUEST_DONE();
}
static void host_check_tsc_msr_rdtsc(struct kvm_vcpu *vcpu)
{
u64 tsc_freq, r1, r2, t1, t2;
s64 delta_ns;
tsc_freq = vcpu_get_msr(vcpu, HV_X64_MSR_TSC_FREQUENCY);
TEST_ASSERT(tsc_freq > 0, "TSC frequency must be nonzero");
/* For increased accuracy, take mean rdtsc() before and afrer ioctl */
r1 = rdtsc();
t1 = vcpu_get_msr(vcpu, HV_X64_MSR_TIME_REF_COUNT);
r1 = (r1 + rdtsc()) / 2;
nop_loop();
r2 = rdtsc();
t2 = vcpu_get_msr(vcpu, HV_X64_MSR_TIME_REF_COUNT);
r2 = (r2 + rdtsc()) / 2;
TEST_ASSERT(t2 > t1, "Time reference MSR is not monotonic (%ld <= %ld)", t1, t2);
/* HV_X64_MSR_TIME_REF_COUNT is in 100ns */
delta_ns = ((t2 - t1) * 100) - ((r2 - r1) * 1000000000 / tsc_freq);
if (delta_ns < 0)
delta_ns = -delta_ns;
/* 1% tolerance */
TEST_ASSERT(delta_ns * 100 < (t2 - t1) * 100,
"Elapsed time does not match (MSR=%ld, TSC=%ld)",
(t2 - t1) * 100, (r2 - r1) * 1000000000 / tsc_freq);
}
int main(void)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
struct ucall uc;
vm_vaddr_t tsc_page_gva;
int stage;
TEST_REQUIRE(kvm_has_cap(KVM_CAP_HYPERV_TIME));
TEST_REQUIRE(sys_clocksource_is_based_on_tsc());
vm = vm_create_with_one_vcpu(&vcpu, guest_main);
vcpu_set_hv_cpuid(vcpu);
tsc_page_gva = vm_vaddr_alloc_page(vm);
memset(addr_gva2hva(vm, tsc_page_gva), 0x0, getpagesize());
TEST_ASSERT((addr_gva2gpa(vm, tsc_page_gva) & (getpagesize() - 1)) == 0,
"TSC page has to be page aligned");
vcpu_args_set(vcpu, 2, tsc_page_gva, addr_gva2gpa(vm, tsc_page_gva));
host_check_tsc_msr_rdtsc(vcpu);
for (stage = 1;; stage++) {
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
switch (get_ucall(vcpu, &uc)) {
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
/* NOT REACHED */
case UCALL_SYNC:
break;
case UCALL_DONE:
/* Keep in sync with guest_main() */
TEST_ASSERT(stage == 11, "Testing ended prematurely, stage %d",
stage);
goto out;
default:
TEST_FAIL("Unknown ucall %lu", uc.cmd);
}
TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
uc.args[1] == stage,
"Stage %d: Unexpected register values vmexit, got %lx",
stage, (ulong)uc.args[1]);
/* Reset kvmclock triggering TSC page update */
if (stage == 7 || stage == 8 || stage == 10) {
struct kvm_clock_data clock = {0};
vm_ioctl(vm, KVM_SET_CLOCK, &clock);
}
}
out:
kvm_vm_free(vm);
}
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